Professor Carol MacKintosh
Cancer and diabetes as disorders of ‘signal multiplexing’ in the vertebrates
Lay summary: Over 500 million years ago, a spineless creature in the Cambrian ocean experienced two successive doublings in the amount of its DNA. These dramatic events triggered the evolution of a new species of animal, which became the ancestor of the backboned fishes, birds, reptiles and mammals, including humans.
My lab is discovering how communication systems inside our cells were boosted by ‘teams’ of proteins generated by these ancient DNA doublings. Orchestrated by other molecules called 14-3-3s, the protein teams form networks that transmit instructions from the many hormones that control the cells in our bodies. These hormones include insulin that instructs our organs to absorb nutrients from our bloodstream and growth factors that stimulate cells to grow and divide. These 14-3-3-regulated networks handle multiple messages better than even the smartest smartphones.
We propose that the fantastic variety of cells and species of backboned animals evolved via different ‘pick-and-mix’ selections of network proteins. However, there is a downside, which is that faults in these networks cause diabetes, neurological disorders and cancers.
Many people are looking for new mutations to explain how cancers work. In contrast, we found that certain team proteins are kept free of mutations because they transmit important instructions for cancers. Drugs that block the mutation-free proteins should therefore be anti-cancer therapies of the future. Amazingly, knowledge of an ancient evolutionary leap provides a cipher to decode the diseases of modern humans.
Scientific summary: My lab is discovering how 14-3-3 proteins regulate a constellation of intracellular targets by docking onto specific pairs of phosphorylated serine/threonine residues, masking functional domains and inducing conformational changes. We use these data to construct regulatory networks that explain phenotypes relevant to cancer, neurodevelopmental and metabolic disorders: For example, growth factors stimulate synchronised shifts in engagement of 14-3-3 with transcriptional and cytoskeletal regulators. Binding of 14-3-3 to the E3 ubiquitin ligase ZNRF2 regulates amino acid activation of mTORC1. The protein AS160 binds to 14-3-3 in response to insulin, while the related protein TBC1D1 binds to 14-3-3 in response to exercise, which helps explain the distinct glucose homeostasis defects in people with mutations in these proteins.
Excitingly, by teasing patterns from our global data we discovered a new ‘signal multiplexing’ paradigm: We found that the human 14-3-3-interactome is highly enriched in families of two to four proteins generated by two genome duplications (2R-WGD) at the Cambrian origin of the vertebrates. Our evidence suggests that binding of 14-3-3s to 'lynchpin' phosphosites helped these protein families to evolved into ‘signal multiplexing’ systems, which integrate more regulatory inputs than would be possible with a single protein. The phenotype of a cell depends on which combinations of 2R-ohnologues are expressed and engaged by the particular signaling pathways that operate in any physiological context.
The ‘signal multiplexing’ concept has many biomedical implications. For cancer, we reasoned that if too many of the 2R-ohnologues that are specific downstream effectors of an oncogenic driver were to suffer deleterious mutations, the driver would lose its efficacy. Then, the cancer cell lineage would die out unless it acquired a different driver mutation that operates via a different mechanism – which might help explain cancer heterogeneity. In contrast, sister 2R-ohnologues that are regulated by signaling networks that are irrelevant to the cancer would be allowed to accumulate multiple mutations. These ideas inspired us to analyse the huge datasets of mutations that are being mapped in many cancers. Indeed, our findings are consistent with our hypothesis that specific 2R-ohnologues are spared mutation in cancers because they are important downstream effectors of oncogenic drivers. These non-mutated 2R-ohnologues therefore become new targets for anti-cancer therapy. We are testing this exciting hypothesis further.
- Level 3 BS32006 Cell Signalling
- Level 3 BS32005 Developmental Biology
- Level 4 BS42013 Advanced Cell Signalling
- Tutor for DJ31001 Art, Science and Visual Thinking
- Senior Honours project supervisor
Ross, F. A., MacKintosh, C. and Hardie, D. G. (2016) AMP-activated protein kinase: a cellular energy sensor that comes in twelve flavours. The FEBS journald.o.i 10.1111/febs.13698
Pubmed: PMC: 26934201
Hoxhaj, G., Caddye, E., Najafov, A., Houde, V. P., Johnson, C., Dissanayake, K., Toth, R., Campbell, D. G., Prescott, A. R. and MacKintosh, C. (2016) The E3 ubiquitin ligase ZNRF2 is a substrate of mTORC1 and regulates its activation by amino acids. eLife. 5d.o.i 10.7554/eLife.12278
Madeira, F., Tinti, M., Murugesan, G., Cole, C., Berrett, E., MacKintosh, C. and Barton, G. J. (2015) 14-3-3-Pred: Improved methods to predict 14-3-3-binding phosphopeptides. Bioinformatics 2015;?doi: 10.1093/bioinformatics/btv133 
Ohman T, Soderholm S, Hintsanen P, Valimaki E, Lietzen N, MacKintosh C, Aittokallio T, Matikainen S, Nyman TA. (2014) Phosphoproteomics Combined with Quantitative 14-3-3-affinity Capture Identifies SIRT1 and RAI as Novel Regulators of Cytosolic dsRNA Recognition Pathway. Mol Cell Proteomics. 2014 Jul 5. pii: mcp.M114.038968. 
Tinti M, Dissanayake K, Synowsky S, Albergante L, MacKintosh C. (2014) Identification of 2R-ohnologue gene families displaying the same mutation-load skew in multiple cancers. Open Biol 4, 140029. [read online]
Chen Q, Quan C, Xie B, Chen L, Zhou S, Toth R, Campbell DG, Lu S, Shirakawa R, Horiuchi H, Li C, Yang Z, MacKintosh C, Wang HY, Chen S. (2014) GARNL1, a major RalGAP α subunit in skeletal muscle, regulates insulin-stimulated RalA activation and GLUT4 trafficking via interaction with 14-3-3 proteins. Cell Signal 26, 1636-1648 
Tinti M, Madeira F, Murugesan G, Hoxhaj G, Toth R, MacKintosh C. (2014) ANIA: ANnotation and Integrated Analysis of the 14-3-3 interactome. doi: 10.1093/database/bat085 
Hoxhaj G, Dissanayake K, MacKintosh C. (2013) Effect of IRS4 Levels on PI 3-Kinase Signalling. PLoS One. 8, e73327. 
Wang H.Y., Ducommun, S., Quan, C., Xie, B., Li, M., Wasserman, D.H., Sakamoto, K., MacKintosh, C. and Chen, S. (2013) AS160 deficiency causes whole-body insulin resistance via composite effects in multiple tissues. Biochem J. 449, 479-489. 
Hoxhaj G, Najafov A, Toth R, Campbell DG, Prescott AR, MacKintosh C. (2012) ZNRF2 is released from membranes by growth factors and with ZNRF1 regulates the Na+/K+ATPase. J Cell Sci 125, 4662-4675. 
Tinti M, Johnson C, Toth R, Ferrier DEK, MacKintosh C. (2012) Evolution of signal multiplexing by 14-3-3-binding 2R-ohnologue protein families in the vertebrates. Open Biol 2, 120103. [Read online]
Neukamm SS, Toth R, Morrice NA, Campbell DG, MacKintosh C, Lehmann R, Häring H-U, Schleicher ED, Weigert C. (2012) Identification of the aminoacids 300-600 of IRS-2 as a 14-3-3 binding region with the importance of IGF-1/insulin regulated phosphorylation of Ser-573. PLoS ONE 7, e43296. 
Ducommun S, Wang HY, Sakamoto K, MacKintosh C, Chen S. (2012) Thr649Ala-AS160 knock-in mutation does not impair contraction/AICAR-induced glucose transport in mouse muscle. Am J Physiol Endocrinol Metab 302, E1036-1043. 
Chen S, Synowsky S, Tinti M, MacKintosh C. (2011) The capture of phosphoproteins by 14-3-3 proteins mediates actions of insulin. Trends Endocrinol Metab. 22, 429-436. 
Johnson C, Tinti M, Wood NT, Campbell DG, Toth R, Dubois F, Geraghty KM, Wong BHC, Brown LJ, Tyler J, Gernez A, Chen S, Synowsky S, MacKintosh C. (2011) Visualization and biochemical analyses of the emerging mammalian 14-3-3-phosphoproteome. Mol Cell Proteomics M110.005751. 
Dissanayake K, Toth R, Blakey J, Olsson O, Campbell DG, Prescott A, MacKintosh C. (2011) Regulation of human capicúa by Erk/p90RSK/14-3-3 signalling impacts on expression of PEA3 Ets transcription factors. Biochem J 433, 515-525. 
Chen S, Wasserman DH, MacKintosh C, Sakamoto K. (2011) Mice with Thr649Ala-TBC1D4(AS160) knock-in mutation are insulin resistant with impaired glucose tolerance and altered GLUT4 trafficking. Cell Metab 13, 68-79. 
Pozuelo Rubio M, Leslie NR, Murphy J, MacKintosh C. (2010) Mechanism of activation of PKB/Akt by the protein phosphatase inhibitor calyculin A. Cell Biochem Biophys 58, 147-156. 
Johnson C, Crowther S, Stafford M, Campbell DG, Toth R, MacKintosh, C. (2010) Bioinformatic and experimental survey of 14-3-3 binding sites. Biochem J 427, 69-78. 
Chen S, MacKintosh C. (2009) Differential regulation of NHE1 phosphorylation and glucose uptake by inhibitors of the ERK pathway and p90RSK in 3T3-L1 adipocytes. Cell Signal 21, 1984-1993. 
Dubois F, Vandermoere F, Gernez A, Murphy J, Toth R, Chen S, Geraghty KM, Morrice NA, MacKintosh C. (2009) Differential 14-3-3-affinity capture reveals new downstream targets of PI 3-kinase signalling. Mol Cell Proteomics 8, 2487-2499. 
Pehmøller C, Treebak JT, Birk JB, Chen S, MacKintosh C, Hardie DG, Richter EA, Wojtaszewski J. (2009) Genetic disruption of AMPK signaling abolishes both contraction- and insulin-stimulated TBC1D1 phosphorylation and 14-3-3 binding in mouse skeletal muscle. Am J Physiol 297, E665-675. 
Hunter RW, MacKintosh C, Hers I. (2009) Protein kinase C-mediated phosphorylation and activation of PDE3A regulates cAMP levels in human platelets. J Biol Chem 284, 12339-12348. 
Treebak JT, Frøsig C, Pehmøller C, Chen S, Maarbjerg SJ, Brandt N, MacKintosh C, Zierath JR, Hardie DG, Kiens B, Richter EA, Wojtaszewski, JFP. (2009) Potential role of TBC1D4 in enhanced post-exercise insulin sensitivity in human skeletal muscle. Diabetologia 52, 891-900. 
Wood NT, Meek DW, MacKintosh, C. (2009) 14-3-3 binding to Pim-phosphorylated Ser166 and Ser186 of human Mdm2 – potential interplay with the PKB/Akt pathway and p14ARF. FEBS Lett 583, 615-620. 
Chen S, Murphy J, Toth R, Campbell DG, Morrice NA, MacKintosh C. (2008) Complementary regulation of TBC1D1 and AS160 by growth factors, insulin and AMPK activators. Biochem J 409, 449-459.